Unit 1 Section 2 Easy

Shared Structures of Eukaryotes and Prokaryotes

• Common structures: plasma membrane, cytoplasm, ribosomes, and DNA.

Unique Structures in Prokaryotes

• Contains circular DNA, cell membrane, cytoplasm, and bacterial flagella.

Unique Structures in Eukaryotes

• Comprises linear DNA, plasma membrane, endomembrane system, mitochondria, chloroplasts, flagella, and cilia.

DNA Storage

• Prokaryotic DNA: stored in a singular circular chromosome located in the nucleoid.
• Eukaryotic DNA: stored in multiple linear chromosomes within the nucleus.

Cytoplasm vs. Cytosol

• Cytoplasm includes all cell structures and fluid.
• Cytosol refers specifically to the fluid component.

Flagella Differences

• Prokaryotic flagella are simpler, rotating to propel the cell.
• Eukaryotic flagella exhibit a complex, whip-like motion.

Bacterial Reproduction

• Bacteria primarily reproduce by binary fission, resulting in two daughter cells.

Pleomorphic Bacteria

• Pleomorphic bacteria can vary in size and shape.

Bacterial Arrangements

• Diplo: pairs
• Strepto: chains
• Staphylo: clusters
• Tetrads: groups of four

Glycocalyx

• A gelatinous layer surrounding some bacterial cells, aiding in protection and attachment.

Forms of Glycocalyx

• Capsule: well-organized, tightly attached.
• Slime Layer: less organized, loosely attached.

Glycocalyx Functions

• Traps nutrients, aids in surface attachment, and helps evade host immune responses.

Flagellum Function

• Provides mobility, allowing bacteria to respond to environmental stimuli.

Flagella Arrangements

• Monotrichous: single flagellum.
• Amphitrichous: one or more flagella at each end.
• Lophotrichous: cluster of flagella at one end.
• Peritrichous: flagella distributed around the cell.

Flagellum Components

• Filament: outer region extending from the cell.
• Hook: connects the filament to the cell surface.
• Basal body: anchors the flagellum to the cell wall and plasma membrane.

Gram Positive vs. Gram Negative Flagella

• Gram Positive: has one set of rings, a single membrane, and a thick peptidoglycan layer.
• Gram Negative: contains two sets of rings, two membranes (outer and inner), and a thin peptidoglycan layer.

Flagellum Movement

• Movement generated by changing flagellar rotation; straight runs occur with stimuli, and more tumbling happens without stimuli.

Endoflagella

• Found in spirochetes, providing unique movement capabilities.

Fimbriae Function

• Hair-like structures used for attachment to specific surfaces.

Pilus Function

• Facilitates bacterial conjugation, transferring genetic material between bacteria.

Cell Wall Function

• Maintains bacterial shape and prevents lysis.

Bacterial Cell Wall Composition

• Contains peptidoglycans made up of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM), along with tetrapeptides.

Gram Positive vs. Gram Negative Cell Walls

• Gram Positive: thick peptidoglycan layer with teichoic acids.
• Gram Negative: thin peptidoglycan layer, outer membrane containing lipopolysaccharides (LPS).

Lipopolysaccharides (LPS)

• Macromolecules found in Gram negative outer membranes, serving as virulent factors and triggering strong immune responses.

Mycoplasma Bacteria

• Lack a cell wall, making them unique among bacteria.

Fluid Mosaic Model

• Describes the cell membrane as a dynamic structure composed of a phospholipid bilayer with proteins that move fluidly.

Phospholipids

• Contain hydrophilic phosphate heads and hydrophobic fatty acid tails, creating a bilayer.

Endospores

• Highly resistant, dormant structures formed by bacteria under harsh environmental conditions.

Metabolism Overview

• Metabolism encompasses all chemical reactions maintaining life, with energy stored as ATP.

Catabolic vs. Anabolic Reactions

• Catabolic reactions break down large molecules, releasing energy.
• Anabolic reactions synthesize larger molecules from smaller ones, consuming energy.

Enzymes

• Catalysts that speed up reactions by binding substrates to active sites; can have cofactors (inorganic) and coenzymes (organic, derived from vitamins).

Active vs. Allosteric Sites

• Active site: where substrate binds.
• Allosteric site: alternative binding site that can affect enzyme activity.

Pathway Modulation Mechanisms

• Competitive inhibition: substrate competes for the active site.
• Non-competitive inhibition: alters enzyme shape, preventing substrate binding.
• Feedback inhibition: end products inhibit an upstream enzyme.

Glycolysis Overview

• Breaks down glucose into 2 pyruvate, divided into an energy investment phase (uses 2 ATP) and an energy payoff phase (produces 4 ATP, 2 NADH, and 2 pyruvate).

Glucose Catabolism Pathways

• Aerobic respiration: uses oxygen as the final electron acceptor.
• Anaerobic respiration: does not use oxygen but employs an alternative electron acceptor.
• Anaerobic fermentation: occurs without oxygen or electron transport chain participation.